Technical development and cost reduction in display elements allow display tiles each composed of multiple display elements (e.g., LEDs) to be frequently used for outdoor and indoor advertising display and other purposes. A display device that includes display panels has been mainly used for displaying nature images and animation moving images, and for other purposes. For indoor uses, since visibility distance gets smaller as pixel pitch gets smaller, display devices provided with such display tiles have been recently used to display images on personal computers at conference rooms and on personal monitoring computers as well. For monitoring uses in particular, personal-computer images that are almost static images have been displayed frequently.
The mainstream of display devices provided with display panels is surface-mount-device (SMD) display devices. Such an SMD display device includes a resin-sealed, small LED display module consisting of LED display elements contained in a cavity molded with ceramic, resin, or other materials. An SMD display device has been used as a large video display device with a pixel pitch of 3 mm or more.
In recent years, however, cost reduction in the LED display elements and achievement in high definition encourage the market to introduce a large video display device in which multiple LED display devices each composed of components densely mounted at a pixel pitch of, for instance, 1 to 2 mm are arranged in the form of tiles.
For instance, Patent Documents 1 and 2 disclose components of an LED display and how to hold these components.
A large video display device in Patent Document 1 is formed of a multi-display system that includes multiple LED display tiles. LED display elements of R, G, and B are mounted on small LED display module substrates so as to extend near the periphery portions of the module substrates. The multiple LED display module substrates, which are arranged in square array to constitute a first LED display panel, are assembled in a support structure. A second LED display tile, similarly to the first LED display tile, is also assembled in the support structure. The first and second LED display tiles are assembled in the support structure while being in substantially close contact with each other with an extremely small gap therebetween. This extremely small gap needs to be of the same size as the pixel pitch.
Patent Documents 1 and 2 describe that the side surfaces of the LED display tiles are processed into a planar shape. These multiple LED display tiles, when combined to each other to form a large-screen video display device in a multi-display system, are coupled to each other in such a manner that the side surfaces of one of the LED display tiles are brought into substantially close contact with the side surfaces of other adjacent LED display tiles.
Patent Document 3 discloses a structure formed of LED display tiles coupled to each other with hook-shaped couplers.